1. Field of the Invention
The present invention generally relates to a device and method for protecting gate terminal and lead, and more particularly to a device and method for protecting gate terminal and lead at stage of scribing and spalling.
2. Description of the Prior Art
In fabrication of a thin film transistor (TFT) liquid crystal display (LCD) device, an array substrate and a color filter substrate are provided respectively, in which a thin film transistor array on the array substrate are formed by thin film deposition, lithographic process, and etching step of semiconductor process. Having been formed the two substrates, an assembling process, a scribing step, and a spalling step is performed. The scribing and spalling steps are to remove peripheral regions on the color filter substrate such that contact plugs of gate terminals on the array substrate can be exposed.
The scribing and spalling steps can be shown in FIG. 1, wherein a display region on an array substrate 100 includes a thin film transistor and a peripheral region includes a gate line 102a. The thin film transistor, covered and protected by a passivation layer 112, has a gate 102, gate insulating layer 104, island semiconductor layer 106, and source/drain 108. A contact plug 114 on gate terminal of the gate line 102a is used to connect driver IC electrically. Another substrate 130, which is also called color filter substrate, has a black matrix 132 on the inner side and assembled with the array substrate 100. In the TFT-LCD fabricating process, after the two substrates are assembled, the scribing and spalling steps are performed. In FIG. 1, scribing line is denoted by dash line, and the contact plug 114 is exposed after scribing.
However, material of the gate insulating layer 104 and the passivation layer 112 is silicon nitride, which has less strain at the stage of scribing and spalling steps to break the two layers. Further, after the gate insulating layer 104 and the passivation layer 112 are broken, gas or origin of pollution will reach the gate line 102a along splits which cause corrosion or oxidation of the gate terminal of gate line 102a. This will cause the display panel fail. Therefore, a solution for resolving issues caused at the scribing and spalling steps is necessary.